OBJECTIVE I: (A) To delineate the molecular mechanism by which double-helical (ds) RNA specifically triggers the production of human interferon (IF). To this end, the structural requirements of the receptor, triggered to product IF, are being mapped with the use of a novel battery of ds RNAs which are interupted either by unpaired bases, bond breakage or modification of their 2'OH groups. (B) To develop novel ds RNA interferon inducers with altered therapeutic ratios. Our recent development of two new inducers, rIn.r(C13,U)n and rIn.r(C20,G)n, has emerged as strong support of this conceptual approach: in the projected 5 year program, we will evaluate these inducers in a number of in vivo systems as well as make any new adjustments in inducer structure which may be dictated by our companion mapping studies (Part A). OBJECTIVE II: Purification of human interferon and modulation of its functional properties. Affinity chromatography will be a new and principal technique for the purification of interferon to homogeneity. To this end a series of lectins of established binding properties will be secured. The binding potential of carbohydrate moiety of interferon will be purposely and deliberately increased by sequential treatment with specific glycosidases. The impact of the carbohydrate moiety of interferon on its charge and size heterogeneity will be evaluated. The understanding and possible control of subunit interaction (i.e., monomer yields (reversibly) oligomer equilibrium), should provide us with additional means of purification. The modulation of carbohydrate moiety and molecular size will be undertaken in order to increase the half life of exogenous interferon in circulation. Our ultimate goal is to optimize conditions for use of interferon in prophylaxis and therapy of viral diseases.